LOCATION.--Lat
41°02'35.5", long 73°53'45.8" referenced to North
American Datum of 1983, Rockland County, NY, Hydrologic Unit 02030101,
on right bank on upstream landward facing section of concrete pier, at
east end of Ferry Road, 1.3 mi east of Piermont, and 24.9 mi north of
the Battery.DRAINAGE AREA.--13,125 mi².PERIOD OF RECORD.--November 2010 to February 2012, June 2013 to
current year.GAGE.--Water-stage recorder. Datum of gage is NGVD of 1929. To
convert elevations to NAVD of 1988, subtract 1.00 ft.REMARKS.--Elevations are not corrected for changes in water
density. Blanks in tables are the result of only one high or low tide
during a day or interruption of record.EXTREMES FOR PERIOD OF RECORD.--Maximum elevation, 7.40 ft, Aug.
28, 2011; minimum elevation, -4.00 ft, Jan. 6, 2018.EXTREMES OUTSIDE PERIOD OF RECORD.--Flood of Oct. 29, 2012,
reached an elevation of 10.68 ft, from floodmark.PERIOD OF DAILY RECORD1.--SPECIFIC CONDUCTANCE:
November 2010 to February 2012, July 2013 to September 2015.
WATER TEMPERATURE: November 2010 to February 2012, July 2013 to
September 2015.INSTRUMENTATION1.--Water-temperature and
specific-conductance satellite telemeter provides 15-minute-interval
readings.REMARKS1.--Interruption of record was due to
malfunction of recording instrument.EXTREMES FOR PERIOD OF DAILY RECORD1.--SPECIFIC
CONDUCTANCE: Maximum, 27,200 uS/cm at 25 °C, Sept. 29, 2013; minimum,
183 uS/cm at 25 °C, Apr. 30, 2011.
WATER TEMPERATURE: Maximum, 31.1 °C, July 22, 2011, July 18, 2013;
minimum, -0.6 °C, Jan. 21, 23, 24, Feb. 3, 2011.1 Water-Quality Records

Elevation observations and tidal predictions for this
station are reported to NGVD 1929. To convert data to NAVD 1988
subtract 1.00 ft. To convert data to MHHW datum subtract 3.07 ft.
To convert data to MLLW datum add 0.90 ft. These corrections vary
from site to site.

NGVD
1929 is the National Geodetic Vertical Datum of 1929,
formerly called "mean sea level" or "Sea Level
Datum of 1929." NGVD 1929 was a general adjustment of the
first-order level nets fit to mean sea level at 26 tide gages in
the US and Canada.NAVD
1988 is the North American Vertical Datum of 1988, which is a
geodetic datum derived from a general adjustment of the
first-order level nets fit to 1 tide gage in eastern
Canada.MHHW is
mean higher high water, which is a site-specific datum determined
by averaging the highest of the 2 high tides that occur each day
over a 19-year tidal epoch. For tide gages with less than 19
years of record, this datum is estimated by correlation with
long-term tide gages.MLLW is
mean lower low water, which is a site-specific datum determined
by averaging the lowest of the 2 low tides that occur each day
over a 19-year tidal epoch. For tide gages with less than 19
years of record, this datum is estimated by correlation with
long-term tide gages.